Timing system



June 25, 1968 L. c. WILCOX 3,389,900

TIMING SYSTEM .35 FIG. 7

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United States Patent 3,389,900 TIMING SYSTEM Lance C. Wilcox, Wilton, Conn., assignor to Electric Regulator Corporation, Norwalk, Conn., a corporation of New York Filed Oct. 28, 1965, Ser. No. 505,551 14 Claims. (Cl. 267-1) ABSTRACT OF THE DISCLOSURE A dashpot-controlled timing system in which the dashpot parts have slow relative movement in one direction and rapid relative movement in the other direction, the speed of movement being controlled by a speedcontrol element which is moved from one operative position to the other after the parts reach one of their operative positions and before they are caused to move substantially toward the other of their operative positions.

The present invention relates to a timing system particularly well adapted, although not necessarily limited, to the actuation of an electrical switch a predetermined period of time after a given manual or electrical signal.

A need exists for an inexpensive, sturdy, reliable, accurate device for measuring relatively short periods of time, on the order of seconds or a small number of minutes. Electrical circuits have been proposed for this purpose, but they are either expensive, delicate, or subject to inaccuracies attendant upon aging or variations in ambient conditions. Mechanical systems involving adjustable damping dashpots have also been proposed. In many instances such devices are excessively large and heavy, in many instances they are overly complex and hence unreliable, and in many instances the accuracy to which they can be adjusted for timing purposes leaves much to be desired. Another major drawback of mechanical systems is that their reset time is generally excessive, that is to say, once they have performed a timing function an appreciable period of time must elapse before they are ready to do so again. Where, as is often the case, these timing systems are used in connection with safety controls of one type or another, the time that it takes to reset the timing system is a time when the safety control is inoperative. Hence a reduction in reset time of even a fraction of a second can be extremely important. Attempts to minimize reset time by causing strong reset forces to act on the moving parts suffer from the drawback that they either cause distortion of the moving parts or necessitate that those parts be made strong and heavy, thereby militating against accuracy and inexpensiveness.

It is a prime object of the present invention to devise a mechanical timing system which is not only simple, light, inexpensive and dependable to a marked degree but which is also characterized by having a very short reset time produced without danger of damage to the moving parts.

The timing is accomplished by mechanically coupling a movable member to a dashpot the damping effect of which can be accurately controlled. As the timing member moves from one position to another, urged in that direction by any appropriate biasing means, the damping effect of the dashpot will so retard its motion as to produce a desired time delay between initiation of that motion and the attainment by the timing member of its utlimate timing position. The time involved may be 3,389,90 0' Patented June 25, 1968 "ice ing dashpot during reset of the timing system, and it is preferred that the bypass be established promptly after varied from a few tenths of a second to several minutes.

the desired time interval has been measured and before the actual reset signal or impetus becomes effective. Hence the timing system is rendered ready, once its timing function has been performed, to carry out a rapid reset operation virtually instantaneously upon command.

To this end the dashpot bypass is controlled by a valve which is movable between open and closed positions. That valve is maintained in closed position during the movement of the dashpot piston for timing purposes. It is engaged by a relatively fixed portion of the system after the piston has moved to its final timing position and is shifted thereby to its open condition. When some appropriate actuating means then acts upon the timing member to return it to its initial position the dashpot piston connected to that member will freely and rapidly move to its initial position, thus making for a minimal reset delay and preventing damaged to or distortion of the moving parts.

In the form here specifically disclosed the dashpot piston is connected to the timing member so as to move therewith. An arm is also connected to the timing member, has a lost-motion connection thereto, and is connected to the dashpot valve. The arm normally extends beyond the timing member in the direction of movement of that timing member during the timing step. That arm engages a relatively fixed part of the system after the timing member has completed its timing movement, and preferably before the reset actuating means is rendered operative.

In the embodiments here specifically disclosed, and as is preferred, the reset actuating means is made directly operative upon said arm, first ensuring that the arm has moved relative to the timing member sufficiently to open the bypass valve (if that has not already occurred) and then acting through the arm upon the timing member, after the lost motion therebetween has been taken up, to move the timing member through its reset movement while at the same time holding the dashpot bypass valve in open condition. In this way a positive safety feature is provided, ensuring that strong reset forces exerted by the reset actuating means will not cause damage to the moving parts.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the construction and arrangement of a timing system as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

FIG. 1 is an elevational view of one embodiment of the present invention designed for timing upon deenergization of a solenoid actuating means, the parts being shown in the position which they assume when the solenoid actuating means is energized;

FIG. 2 is a fragmentary view on an enlarged scale similar to FIG. 1 but showing the solenoid actuating means de-energized and the timing parts in an intermediate position during the timing operation;

FIG. 3 is a view similar to FIG. 2 but showing the parts at the end of the timing operation;

FIG. 4 is a top plan view taken along the line 4-4 of FIG. 3;

FIG. 5 is a cross sectional view, on an enlarged scale, of the central portion of a dashpot piston, showing a type of by-pass valve which can be employed;

FIG. 6 is an elevational view of a second embodiment of the present invention designed for timing upon energization of a solenoid, the parts being shown with the solenoid in de-energized condition;

FIG. 7 is a view on an enlarged scale of the system of FIG. 6, showing the solenoid actuator energized and the parts in an intermediate position during the timing operation; and

FIG. 8 is a view similar to FIG. 7 but showing the parts at the end of the timing operation.

The system of the present invention is here specifically disclosed as provided with an actuating means generally designated 2 in the form of a solenoid and an output means generally designated 4 in the form of an electrical switch, the switch 4 being shifted from one output condition to another by movement of a movable member generally designated 6, the movement of that member 6 in one direction or another being controlled, or initiated, by the actuating member 2. It will be understood that in its broader aspects the present invention is not limited to the specific disclosure, and that in particular different actuating means 2 and different output means 4 could be employed. For example, a manual push button could be used for the actuating means 2 and a mechanical latch could be tripped for the output means 4.

The actuating solenoid 2 is mounted on a support 8 (shown only in FIG. 1), and comprises an actuating winding 10 and plunger 12 which is normally urged into withdrawn position (its upper position in FIGS. 1-3 and its lower position in FIGS. 6-8) by means of spring 14 compressed between the bracket 16 and a washer 18 carried by the plunger 12. The plunger tip 12a is withdrawn within the windings 10 and the plunger tip 12b and the Washer 18 are extended from the winding 10 when those windings 10 are de-energized (see FIGS. 2, 3 and 6), the spring 14 providing the force for this movement, the plunger tip 12a being projected downwardly out from the winding 10 and the plunger tip 12b and the washer 18 being moved down toward the windings 10, compressing the spring 14, when that winding is energized, as is shown in FIGS. 1, 7 and 8.

The output member 4 is also fixedly mounted on the support 8. As here disclosed it comprises a casing which houses what is conventionally known as a snap switch, that switch being actuated by a button 22 spring urged up from the upper casing surface 24. The button 22 is movable between upper and lower positions (shown respectively in FIGS. 3 and 8 and FIGS. 1 and 6), and will actuate the snap switch to which it is operatively connected in accordance with its upper or lower position, the switch being open for one of the positions of the button 22 and the switch being closed for the other position thereof. Preferably the button 22 is effective to actuate the switch slightly before the button 22 reaches its maximum upper position.

The timing member 6 comprises an arm 24 having a pair of laterally spaced downwardly extending projecting portions 26 at one end thereof, those portions engaging the switch casing 20, thereby to support the arm 24 for pivotal movement. Laterally spaced fingers 28 extend angularly down from the arm 24, at least one of the fingers overlying and being engaged by the switch button 22. For balancing purposes a pair of upwardly spring-urged buttons 22 may be provided, one active on each of the fingers 28. The precise position of the fingers 28 relative to the arm 24, and hence their action on the switch button 22, may be adjusted by means of screws 30 which extend through the downwardly projecting arm portion 26 and bear against the inclined portions of the fingers 28. A counterweight 34 is secured to the arm 24 by means of the screws 30 and by any desired additional securing means, such as the screw 32 (see FIG. 4).

A damping dashpot, generally designated 36, is also mounted on the support 8. It comprises a cylinder 38, shown as formed of glass, within which a closely fitting piston 40 sealingly slides. The top of the cylinder 38 is open. The bottom of the cylinder 38 is, as is conventional, closed except for an adjustable leakage opening the size of which, and hence the rate of air fiow therethrough, is adjustable through rotation of the nut 42.

The arm 24, at its free end, carries a block 44 provided with end slot 46, vertical aperture 48 and upwardly projecting headed rivet 50. A Wire link 52 engages the interior of the dashpot piston 40 and is received within the slot 46, thereby operatively connecting the dashpot piston 40 to the timing member 6 for simultaneous movement.

The central portion 401: of the dashpot piston 40, shown in enlarged cross sectional view in FIG. 5, is provided with a bypass passage extending therethrough, that passage comprising openings 54 which extend to the bottom of the piston 40, chamber 56 which communicates with the openings 54 and which terminates at its upper edge in surface 58, and opening 60 which communicates between the chamber 56 and the space above the piston 40. Received within the chamber 56 with clearance therearound is valve ball 62. The valve ball 62 is normally urged upwardly to sealing engagement with the surface 58 by means of spring 64 retained in any appropirate fashion at the lower portion of the chamber 56. The vertical clearance between the valve ball 62 and the chamber 56 is such that, as shown in FIG. 5, the valve ball 62 may be forced downwardly against the action of the spring 64 and away from the surface 58. When the valve ball 62 engages with the surface 58 the bypass passage through the piston 40 is closed; when the valve ball 62 is forced downwardly against the action of the spring 64, as shown in FIG. 5, the bypass passage through the piston 40 is open. A valve link 66 is connected to the valve ball 62, extends upwardly from the piston 40, passes freely through the aperture 48 in the block 44, and extends up above the upper surface of the block 44.

A second and preferably resilient arm 68 is secured to the arm 24 at point 70, that point 70 being located to the side of the actuating means 2 opposite from the damping dashpot 36. The arm 68 extends along and over the arm 24, and its free end 72 is located over the upper tip of the dashpot valve link 66. The normal resilliency of the arm 68 is such as to cause it to be biased upwardly away from the arm 24 and away from the tip of the dashpot valve link 66, its movement in this biased direction being limited by the headed rivet 50 the shank of which passes loosely through an aperture 74 (see FIG. 2) in the arm 68.

The embodiment of FIGS. 1-4 is designed to time an interval after the solenoid actuating means 2 is de-energized. The stand-by or rest postion of the parts is shown in FIG. 1, with the actuating means 2 energized, the plunger 12 moved downwardly with its tip 12a projected downwardly, the arm 24 pivoted in a counter-clockwise direction so as to move the dashpot piston 40 downwardly, the finger 28 then being in a depressed position forcing the switch button 22 downwardly and causing the output switch 4 to assume a particular condition, such as an open circuit condition. It will be noted that the arm 68 has been moved downwardly by the plunger tip 12a to a position closely toward the arm 24, thus moving the valve link 66 downwardly, forcing the valve ball 62 down to its position shown in FIG. 5 and opening the bypass passage through the diaphragm piston 40.

When the actuating solenoid 2 is de-energized the plunger 12 moves upwardly, withdrawing its tip 12a from the arm 68. Immediately the arm 68 rises relative to the arm 24, thus urged both by its own resilient bias and by the action of the spring 64 acting through the valve ball 62 and valve link 66. Hence the valve ball 62 will move up into engagement with the surface 58, closing the bypass passage through the dashpot piston 40. Thereafter the valve ball 62 and valve link 66 will be arrested in their upward movement relative to the piston 40. The arm 68 will, however, continue to rise until stopped by the headed rivet 50, a clearance then existing between it and the upper tip of the valve link 66, as is shown in FIG. 2. The arm 24 will pivot in a clockwise direction, thus urged by any suitable biasing means, such as the resilient force tending to urge the switch button or buttons 22 upwardly, which force is transmitted to the arm 24 by means of the fingers 28. The speed with which the arm 24 will thus pivot will be determined not only by the magnitude of the biasing means active thereupon but also and primarily by the damping effect exerted by the dashpot 36. The extent of that damping eifect is controlled through rotation of the nut 42. The damping effect of the dashpot 36 will be appreciable and accurate.

The arm 24 will continue to pivot in a clockwise direction through the intermediate position shown in FIG. 2 toward its final position shown in FIG. 3, eventually permitting the switch button 22 to rise sufiiciently to cause the switch to shift to its other operative condition, such as a closed circuit. Thereafter the switch button 22 will continue to rise somewhat, urging the arm 24 to continue to pivot in a clockwise direction, and this will continue until the arm 68 engages a relatively fixed part of the system (shown in FIG. 3 as a corner 2a of the actuating solenoid 2) and is moved thereby down toward the arm 24 (or, more properly, is arrested thereby while the arm 24 is thereafter permitted an appropriate degree of upward movement). When this occurs the upper tip of the valve link 66 will be engaged and depressed by the free end 72 of the arm 68, thus moving the valve ball 62 downwardly against the action of the spring 64 and opening the bypass passage through the dashpot piston 40.

When the timing system is to be reset the solenoid actuating means 2 will be re-energized and the tip 12a of the plunger 12 will be projected downwardly. In thus moving it will engage the arm 68 and force that arm downwardly, thereby causing the arm 24 to pivot in a counterclockwise direction and causing the dashpot piston 40 to move downwardly. Because the bypass passage through the dashpot piston 40 was already open, the movement of the parts back to their initial timing position commences immediately and is carried out rapidly.

Even it, through design or accident, the valve ball 62 should not have been pushed down to valve-open position at the end of the timing stroke, the action of the solenoid plunger tip 12a when the solenoid actuating means 2 is energized will positively effectuate the downward movement of the valve ball 62 to valve-open position immediately, and before any appreciable rest force is exerted on the arm 24. This represents a significant safety factor, since the exertion of a large reset force is desirable to effect reset quickly, but the exertion of a large force upon a relatively thin element such as the arm 24, should the movement of that element be highly damped, might result in damage to or distortion of that element. This is also important when a reset signal is given while the timing operation is in process.

The embodiment of FIGS. 6-8 is essentially the same as that of FIGS. 1-4 except that the solenoid actuating means 2 is reversed in position, whereby the arm 24 is pivoted in a counter-clockwise direction to its initial timing position when the solenoid actuating means 2 is deenergized (see FIG. 6) and accomplishes its timing action beginning with the instant that the solenoid actuating means 2 is energized (see FIGS. 7 and 8). In this embodiment, as in the first described embodiment, when the arm 24 reaches the end of its timing movement and appropriately actuates the output switch 20, it moves somewhat further beyond that position and the arm 68 is engaged by a relatively fixed part (here the portion 12b of the solenoid plunger 12), after which the valve link 66 is positively depressed relative to the piston 40, thereby opening the bypass passage through the piston 40.

The disclosed construction, it will be seen, is exceedingly simple, light, and inexpensive. The movement of the moving parts may be very readily timed so as to accurately measure time intervals from a period of a second or less to a period of several minutes. Reset is extremely rapid, is accomplished by the exertion of appreciable reset forces, but the parts are so arranged as to virtually eliminate the possibility of excessive resistance to the reset forces, thereby ensuring long life without damage or distortion.

While but a limited number of embodiments of the present invention have been here disclosed, it will be appreciated that many variations may be made therein, all within the scope of the instant invention as defined in the following claims.

I claim:

1. In a timing system comprising a member movable between first and second operative positions, biasing means urging it to said first position, actuating means operatively connected to said member and active thereon to cause it to move to said second position, and a timing dashpot comprising a pair of relatively movable parts.

one of which is operatively connected to said member; the improvement which comprises means for causing said dashpot parts to have slow relative movement when said member moves in one direction and to have rapid relative movement when said member moves in the opposite direction, said last mentioned means comprising a speed-control element movable between operative positions corresponding respectively to said slow and rapid relative movements respectively, and means active on said speed control element to cause it to move from one of its operative positions to the other after said member reaches one of its operative positions and before said actuating means causes said member to move substantially toward the other of its operative positions.

2. The timing system of claim 1, in which said speedoontrol element is shifted from its slow-movement to rapid-movement position after said member has moved to its first position.

3. The timing system of claim 2, in which one of said dashpot parts is fixed and the other is movable, and in which said speed-control element and said member are bperatively connected to said movable dashpot part.

4. The timing system of claim 2, in which said one of said dashpot parts comprises a dashpot piston with a passage therethrough and said speed-control element comprises a normally closed valve active on said passage, said means active on said speed-control element comprising a part connected to said valve for actuating the latter and extending from said piston in the general direction from said second to said first position of said member.

5. The timing system of claim 2, in which said means active on said speed-control element is positioned to one side of said member and normally spaced therefrom by a predetermined distance, said speed-control element being located closer than said predetermined distance to said means active thereon.

6. The timing system of claim 1, in which one of said dashpot parts is fixed and the other is movable, and in which said speed-control element and said member are operatively connected to said movable dashpot part.

7. The timing system of claim 1, in which said means active on said speed-control element is positioned to one side of said member and normally spaced therefrom by a predetermined distance, said speed-control element being located closer than said predetermined distance to said means active thereon.

8. The timing system of claim 1, in which said one of said dashpot parts comprises a dashpot piston with a passage therethrough and said speed-control element comprises a normally closed valve active on said passage, said means active on said speed-control element comprising a part connected to said valve for actuating the latter extending from said piston in the general direction from said one of said member operative positions to the other.

9. A timing system comprising a support, a member pivotally mounted thereon, biasing means active on said member to urge it to pivot in a given direction, actuating means operatively engageable with said member so as to cause said member to pivot in a direction opposite to said given direction, a damping dashpot comprising a cylinder mounted on said support and a piston slidable in said cylinder, said piston having a bypass passage therethrough, a valve mounted on said piston and operatively connected to said passage to open and close the latter, a piston link connected between said piston and said member, a valve link connected at one end to said valve for actuating the latter between passage-open and passageclosed positions and extending toward said member, an arm operatively connected to said valve link and operatively connected to said member so as to move therewith and have motion relative thereto and normally located between said member and a part fixed relative to said support, said part and said arm engaging when said member moves toward said part, thereby to move said arm relative to said member and to move said valve link and thus move said valve to one of its operative positions.

10. The timing system of claim 9, in which said arm is fixed to said member at one point, is operatively connected to said valve link at another point, and is engaged by said part between said points.

11. The timing system of claim 9, in which said arm is fixed to said member at one point, is operatively connected to said valve link at another point, and is engaged by said part between said points, said arm comprising the operative connection between said member and said actuating means.

12. The timing system of claim 9, in which said part is positioned to the opposite side of said member from said dashpot, said arm being mounted on said member from said dashpot, said arm being mounted on said member so as to extend beyond the actuating-means side of said member and being movable relative to said member toward and away from said part.

13. The timing system of claim 12, in which said arm is fixed to said member at one point, is operatively connected to said valve link at another point, and is engaged by said part between said points.

14. The timing system of claim 12, in which said arm is fixed to said member at one point, is operatively connected to said valve link at another point, and is engaged by said part between said points, said arm comprising the operative connection between said member and said actuating means.

References Cited UNITED STATES PATENTS 2/1966 COhen 335-61 

